from math import fsum

if __name__ == "__main__":
    array = [float(input("请输入实数："))]
    while not array[-1] == 0:
        array.append(float(input("请输入实数：")))
    print("这些实数的均值为%f"%(fsum(array) / (len(array) - 1) if len(array) > 1 else 0))